At 08:00 PM 14/09/2008 -0400, Adam Hammond wrote:
>...anodizing does help
>contribute to the "disposability" of many newer products. Anodizing
>wears off, collects dirt, and eventually looks ugly. Non-anodized
>aluminum, with some polish, will stay looking beautiful forever...
>
>See my complete reflections (pun very much intended) here, along with
>some photographic demonstrations:
>
>http://twoseriousbikes.blogspot.com/
Not sure that I would agree with you, Adam.
When done properly, anodizing is much harder and much more durable than plain polished aluminum. In fact, parts that don't have a perfectly smooth or machined finish need to be first polished before they are anodized. Anodized parts wear for a very long time before scratches appear. I would bet that you'd have to ride a bike with anodized cranks for a year before it would have toes strap scuffs on it like those that you would get on plain polished aluminum after just one day. If you try polishing anodized aluminum with metal polish, you won't see any difference unless you first attack it with something much more abrasive, like emery cloth. When you polish plain aluminum, you'll see a black residue right away, because it's so much softer.
Of course, I do know where you're coming from. Vintage anodized parts, 30 or more years old, will undoubtedly have some scratches that make them look shabby and you can't just shine them up with a rag and polish in 10 minutes and make them look new again because the anodizing is just too hard. So what you do is spend hours sanding and polishing them until you have your mirror finish. But within a few weeks they're dull again and have to be re-polished. Worse yet, if you ride on salted or gravel roads, these unprotected aluminum parts will corrode and you're back to square one.
No, while anodizing may be a method of making aluminum bits more durable and retain their lustre for a relatively long time, I would most certainly not put it in the same class as carbon fibre. A couple of months ago my neighbour was proudly showing me his $7000 carbon fibre mountain bike, which was almost as light as my lightest vintage road bike. Trouble is that if I had it, I'd be afraid to take it off-road for fear of dropping it and poking a hole through the frame. Now, that's throw-away.
Another way of protecting aluminum and keeping it shiny is a coat of clear lacquer. That's what they use on the alloy wheels you see on the fancier cars today. However, if you scrape a curb or drive through the salt in the winter, they start to look pretty crappy. Okay for wealthy folks who buy new cars every 2-3 years, but basically throw-away. I know people who have stripped the lacquer and polished up alloy car wheels, but they have to keep shining them up every week, which is fine for show cars, but not to practical for a daily driver.
So, there's nothing wrong with anodizing on new parts, so long as it's quality hard anodizing. The problem arises with old vintage parts that have become damaged over decades. It's too bad the process isn't as simple as painting so we could strip and re-anodize these bits ourselves, or find a shop to do it cheaply.
John Betmanis
Woodstock, Ontario
Canada